Electrode for electric tube-lamps



PATBNTBD JAN. 19, l1904:.

9.1M. MOORE. ELBGTRODB PoR ELECTRIC TUBE LAMPS.

APPLIUATION FILED FEB. 2`l 1903.'

THE Nonms vargas co, PnUTo-L|THo..wAsH|NoToN, DA c.

No. l-(49,999.

UNITED STATES Patented January 19, 1904.

PATENT OFFICE.

ELECTRODE FOR ELECTRIC TUBE-LAMPS.

SPECIFICATION forming part of Letters Patent No. 749,999, dated January 19, 1904.

Application filed February, 1903.l Serial No. 145,185. (No model.) I

.resident of Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Electrodes for Electric Tube-Lamps, of which the following is a specification.

My invention relates to that class of devices in which electric energy is supplied to a body or column of rarefied air, gas, or vapor contained within a suitable receptacle for the purpose of rendering said gas or vapor luminous or for any other purpose.

My invention relates more particularly to that class of devices of the character above stated wherein the energy is applied indirectly through an exterior cap or sheath applied to the surface of the receptacle-as, for instance, in that form of electric tube-lamp heretofore devised by me wherein the conducting electrode or sheath consists of a coating of graphite adhering to the exterior surface of the tube and covering a greater or less extent -of its superficial area, so as to provide means for transferring alternating electric energy to the contents of the tube at opposite ends thereof, so as to render the intermediate column of gas or vapor luminous. In some prior cases a coating of metal foil has been used instead of graphite. In apparatus of this character it has been diiiicult to operate the device with large currents or currents of high potential,

owing t'o the tendency of breaking down of the wall of the receptacle or tube at the forward edge or portion of the conducting cap or coating by the discharge of current.

Y rlhe aim of my present invention is to avoid this difliculty and to permit the device to be operated by currents oflarge quantity and high potential, to which end the invention consists, substantially, in providing'means for excluding air from the point of junction of the luminous portion of the tube and the conducting-cap by which the energy is supplied to the contents of said tube.

' In one manner of carrying out my invention I propose to employ, in combination with the previous form of graphite or other cap, a

suitable air-tight inclosure, which surrounds said cap and is joined to the tube at a point beyondy the junction-point mentioned and to exhaust the air from said air-tight inclosure. In the preferred form of my invention I use said inclosure as the holder for a conducting liquid, like mercury, said mercury becoming then the means not only for excluding the air, but also operating as the conducting-cap, and thereby dispensing with the necessity for using an adherent coating of graphite or other material. j

In the accompanying drawings, Figure l illustrates the end of the tube provided with a cap of the kind previously employed by me. Fig. 2 shows in longitudinal section a construction embodying my present invention. Fig. 8 illustrates another form of my invention in which mercury is employed. Fig. 4

shows a modilicationof my invention in which `mercury is employed. Fig. 5 illustrates a further modification.

Referring to Fig. 1, the gas-containing tube (indicated at 2) is shown provided at its sealed end with an adherent coating of graphite 8, with which connection is made by conducting band or ring 9, as described in my prior patent, No. 646,858, dated April 3, 1900. In this construction of exterior cap or electrode, as with all other forms in which the portion 8 consists of an adherent coating of conducting material, diiiiculty is experienced from the tendency of the electric currents to crack and break the tube or receptacle at .the junction A between the luminous portion 2 of the tube and thepart or portion bearing the adherent cap or coating. There is also, particularly when considerable energy is passed through the tube, an objectionable crackling sound, caused by purple streamers of electricity which pass throughthe air from the coating to the tube over the junction marked A. One method heretofore resorted to by me for removing this objection has been to greatly increase the length or area of the conducting-cap. Although this expedient re- Inoves the diiculty above mentioned, it of itself introduces another objection-to wit, an undue size or length of cap 8. I have found by experience that the difficulty may be effectively avoided by insulating the junction A from Contact with the external air, and to attain this end I propose to provide the end of the tube with a supplemental inclosure 3, (shown in Fig. 2,) forming an air-tight chamber, from which the air may be exhausted, and which inclosure has an air or liquid tight junction with the tube 2, as shown, forward of the point A or junction between the cap 8 and the portion 2 of the tube. Then the inclosure is of glass, the junction may be sealed by fusion. It is obvious that a mcchanical seal after the manner of a stufngbox may be employed at this point. Vith a good-exhaustion of air from the inclosure the terminal constructed as shown in Fig. 2 is capable of handling several times as much energy as the form shown in Fig. l with the same facility.

Instead of using an inclosure 3 which is completely air-tight and exhausting air therefrom said inclosure may take the form shown in Fig. 3, where I show it as constructed and arranged to contain a body of mercury 4 or other good conducting liquid, which completely envelops the end of the tube and which is in electrical connection with any suitable source of energy by means of a conductor 5, properly supported and having its exposed or conducting end immersed in the body of mercury. In this instance the body of mercury excludes air from the junction-point A and prevents the diiiiculty before mentioned. It is important that the mercury should completely cover the end of the tube, as shown. If the mercury should only stand at the level indicated by the line m a', so as to expose the upper end of the tube to the air, the same difficulty before mentioned would exist, but in a modified degree, at the point marked B.v In this modification of my invention it is obvious that the mercury or other conducting liquid serves as the conducting-cap or electrode by which energy is transferred inductively through the walls of the tube to the contents thereof. In some cases it is desirable to have the terminal of the tube extend in a downward direction instead of upward. rIhe envelop may be applied in the manner shown in Fig. 4 and may form a complete inclosure, as indicated, excepting at the point where a tube 6 is provided for insertion or withdrawal of the mercury. In order to avoid trapping air in the contracted space at A, it is desirable that the inclosure should be completely exhausted of air before mercury is introduced. Instead of supporting a wire 5 so that it may dip into the mercury, as shown in Figs. 3 and 4, said wire may be sealed in the receptacle or inclosure after the manner of the leadingin wire for an electric incandescent lamp and as shown in Fig. 5.

It is obvious that my invention may take many other forms and the shape of the inclosure 3 may be varied 1n many ways, and 1t 1s valso obvious that my invention is not confined to the use of any particular conducting liquid 4, since my invention consists, broadly, in the provision of suitable means for excluding air from the point of junction A or B between the energy-transferring electrode and the tube or receptacle containing the gas or vapor.

I claim as my invention# l. The combination with a tube or other re ceptacle containinga rareied gas or vapor, of an exterior energy-transferring electrode and means for excluding air from a junction-point between said electrode and said tube or receptacle.

2. The combination with a lamp consisting of a tube or receptacle containing a gas or vapor rendered luminous by the application of electric energy, of a supplemental envelop 3 applied to said tube or receptacle as and for the purpose described.

3. rIhe combination with a tube or other receptacle containing a rareiied gas or vapor, of an exterior conducting-cap or electrode consisting of a body of mercury or other good conductor in which the exteriorwalls of the receptacle are immersed. v

4. The combination with a tube or other receptacle containing a rareiicd gas or vapor, of an exterior conducting-cap or electrode consisting of a conductor in which the exterior walls of the receptacle are immersed.

5. In a lamp consisting of a tube or receptacle containing a gas or vapor to be rendered luminous by the application of alternating electric energy, an exterior conducting-cap or electrode consisting of a body of mercury or other good conducting liquid in contact with the exterior wall of said receptacle.

6. The combination with asealed tube or receptacle containing a gas or vapor, of an exterior conducting-cap or electrode consisting of a body of mercury or other good conductor in contact with the wall of said gas-containing receptacle and means for insulating the same from contact with the air at the edge of its area of contact.

7. The combination with a sealed tube or receptacle containing a gas or vapor, of an exterior conducting-cap or electrode consisting of a body of mercury or other good conductor in contact with the wall of said gas-containing receptacle and sealed at the point of transference of the electric energy to the gas, as and for the purpose described. l

8. In an electric lamp consisting of a glass tube or other receptacle containing a gas or vapor adapted to be rendered luminous by the application of alternating Aelectric energy, a liquid-containing receptacle of glass sealed to said tube and adapted to hold the body of liquid in contact with the outer wall of the gas- IOO IIO

containing receptacle as and for the purpose described. f I

9. 1n an electric tube-lamp, the combinatio with a gas or vapor containing tube of glass, of an exterior liquid-containing receptacle sealed thereto, and a leading-in wire or conductor sealed in said outer liquid-containing receptacle, as and for the purpose described. 10. In an electric tube-lamp, the combination with a gas or Vapor containing tube of glass, of an exterior receptacle sealed thereto, and a leading-in wire or conductor sealed .in said outer receptacle, as and for the purpose described. l

l1. The combination with a vacuum-tube electrode applied tothe exterior of the tube or receptacle, of means for excluding air from said electrode.

. 12. The combination with a tube or other receptacle containing a rareed gas or vapor, 2n i DANIEL MCFARLAN MOORE.

Witnesses:

J. GALLWITZ, E. L. LAWLER. 

